There was a lot of piano played in a lot of the Transatlantic Sessions (1 to 3) and I thought a lot of that worked remarkably well. A lot of Scottish music works remarkably well with the piano as an accompanying instrument (Fiddlers Bid are a favourite of mine at the moment). Capercaillie feature keyboards a lot and that seems to work for me.

Some examples - Sam Lakeman, Cara Dillon and Paul Brady or Cara Dillon again or Ae Fond Kiss - Karen Matheson or Julie Fowlis